Huh? IR goes up... volts over the battery go up, so volts on motor should drop... thus Amps/Watts would fall too.... not go up.
It would be handy to see a logger, so it charts them all.

I have never encountered that case....... but maybe the motor gets HOT, its impedance goes DOWN for some reason, thus Amps increase (even for the same volts) and it burns more and more power for nothing (because it all goes in heat).
As a possible explanation if the battery is known to be fine to cope (eg that 65C rating).
The IR500 motor might be "pretty good" but not truly "good enough" for its application.

"but maybe the motor gets HOT, its impedance goes DOWN for some reason, thus Amps increase (even for the same volts) and it burns more and more power for nothing (because it all goes in heat"

I don't believe the impedance will go DOWN on any motor that is getting hot. The impedance will rise with temp. I do agree that it is running inefficiently at WOT on 5s. Will test again with a 4s lipo tomorrow. At this point I still plan on using this setup in the habu on 5s, just limiting wot to short bursts. I knew it was going to be a "hot" setup when I ordered it, looks like 1/2 to 3/4 throttle for safe flying.

Hello friends,
I want to use Turnigy sk3 3300kv on this blade w/ turnigy A spec 1300mAh 45C/90C and i'm going to use it around 10 seconds only
my question is, how much thrust will i get ? And will the battery stand for 10 seconds at full thrust ?
And, is there any recomendation to maximize its power ? Because i need maximum thrust for only 10 seconds.
Thank you